Within the field of radio communications, the technology known as “spread spectrum” is often employed in order to make a deterministic signal appear stochastic. Such a signal will be similar to white noise, thus making it very difficult to understand an intercepted signal.
One known method for achieving “spread spectrum” is Fast Frequency Hopping, abbreviated as FFH. The frequency employed at any given moment in such a system is often determined by a random frequency generator, which is driven by a synchronization signal known both to the receiver and the transmitter, in order to enable the receiver to “follow” the frequencies used by the transmitter.
A feature common to many FFH-systems of the kind described above is that each “state”, or, in this case, frequency, has a strong dependency on the frequency or frequencies used previously. If the transmitter and receiver for some reason “lose” their synchronization, the transmitter and receiver will be out of phase, meaning that the receiver will not be able to “hear” the transmitter.